The long-term goal of this research is to improve the quality of men's lives after a diagnosis of prostate cancer by facilitating the patient's treatment decision-making. An estimated 343,500 American men will face a diagnosis of prostate cancer in 1997. The majority of prostate cancers are diagnosed without clinical evidence of metastatic spread. Localized prostate cancer (LPC) can be treated with one or more of several modalities including observation alone, surgery, cryosurgery, hormonal therapy, brachytherapy, or external beam radiation therapy. Efficacy and complication rates vary widely even within treatment modalities. Randomized trials comparing treatments are at least a decade away from meaningful results and even then may not demonstrate significant differences in survival. Clinicians provide much information to patients, but the information provided is often heavily influenced by the specialty of the clinician. Computerized decision support aids that exist for treatment decision-making in prostate cancer assess characteristics of a man that are considered relevant by physicians, but characteristics which are personally relevant to the patient, and the process through which the patient's decisions are made, are unknown. Care providers have not developed, comprehensively investigated, nor provided data-based interventions to facilitate the insight, prioritizing, and decision-making that is required of a man with a diagnosis of LPC. The purpose of this study, using prospective, descriptive, qualitative and quantitative methods, is to systematically document relevant aspects of treatment decision-making in men with LPC and develop a decision support system which nurses and other clinicians can use to prepare the patient to engage in the decision-making process. Six focus groups and 20 individual in-depth interviews will be conducted to evaluate the treatment decision-making aspects, information use, expectations, preferences, and process components perceived by men with LPC. Physicians will be interviewed to obtain a description of priority information given to specific patients and factors upon which the prioritizations are based. After analysis of data from the focus groups and interviews, a questionnaire packet will be designed including both standardized instruments and a new questionnaire specific to decision-making aspects, information use, expectations, and preferences of men with LPC. The questionnaire data will be collected from 300 men in the Seattle and Pittsburgh areas who have a new diagnosis of prostate cancer before treatment has been initiated and 6 months after treatment has begun. A prototype decision support aid will be developed and a pilot test conducted to guide men through the personal issues, expectations, and preferences to be considered in treatment decision-making after a diagnosis of prostate cancer.